Access Method for Multi-Layer Holographic Recording Medium

Abstract

An access method for a multi-layer holographic recording medium which method enables rapid access to the recording position of desired data. In a multi-layer holographic recording medium 16 , data pages formed by two-dimensionally arranging a plurality of data blocks for recording data are angle-multiplex-recorded in respective holographic recording layers. In a multi-layer holographic memory reproducing apparatus 10 , a data block is accessed based on a layer number assigned to each of the holographic recording layers, a number assigned to each of data pages in each of the holographic recording layers, and a number assigned to each of data blocks in each of the data pages.

1 . An access method for a multi-layer holographic recording medium in which data pages formed by two-dimensionally arranging a plurality of data blocks for recording data are angle-multiplex-recorded in respective holographic recording layers of a multi-layer holographic recording layer formed by laminating a multitude of said holographic recording layers, the access method for the multi-layer holographic recording medium comprising accessing the data blocks based on a layer number assigned to each of the holographic recording layers, a number assigned to each of the data pages in each of the holographic recording layers, and a number assigned to each of the data blocks in each of the data pages.  
   
   
       2 . The access method for a multi-layer holographic recording medium according to  claim 1 , wherein the data pages are shift-multiplex-recorded over the entire area of the holographic recording layers.  
   
   
       3 . The access method for a multi-layer holographic recording medium according to  claim 1 , wherein the number assigned to each of the data blocks is identified by a row number and a column number assigned to each of the data blocks in the data pages.  
   
   
       4 . The access method for a multi-layer holographic recording medium according to  claim 2 , wherein the number assigned to each of the data blocks is identified by a row number and a column number assigned to each of the data blocks in the data pages.  
   
   
       5 . The access method for a multi-layer holographic recording medium according to  claim 1 , wherein the layer number assigned to each of the holographic recording layers is identified by a number assigned to each of two-dimensional optical detectors each of which is provided for a respective one of the holographic recording layers in order to detect the data pages which are angle-multiplex-recorded.  
   
   
       6 . The access method for a multi-layer holographic recording medium according to  claim 5 , wherein the two-dimensional optical detectors are constituted by an imaging device having the same two-dimensional pixel arrangement as the pixel arrangement of the data pages and the data pages are read out on a row-by-row basis by means of the imaging device.  
   
   
       7 . The access method for a multi-layer holographic recording medium according to  claim 1 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       8 . The access method for a multi-layer holographic recording medium according to  claim 5 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       9 . The access method for a multi-layer holographic recording medium according to  claim 6 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       10 . The access method for a multi-layer holographic recording medium according to  claim 1 , comprising: a process of successively reading a first data page to a last data page in the holographic recording layer; and a process of changing to the holographic recording layer to be read out.  
   
   
       11 . The access method for a multi-layer holographic recording medium according to  claim 5 , comprising: a process of successively reading a first data page to a last data page in the holographic recording layer; and a process of changing to the holographic recording layer to be read out.  
   
   
       12 . The access method for a multi-layer holographic recording medium according to  claim 6 , comprising: a process of successively reading a first data page to a last data page in the holographic recording layer; and a process of changing to the holographic recording layer to be read out.  
   
   
       13 . The access method for a multi-layer holographic recording medium according to  claim 2 , wherein the layer number assigned to each of the holographic recording layers is identified by a number assigned to each of two-dimensional optical detectors each of which is provided for a respective one of the holographic recording layers in order to detect the data pages which are angle-multiplex-recorded.  
   
   
       14 . The access method for a multi-layer holographic recording medium according to  claim 3 , wherein the layer number assigned to each of the holographic recording layers is identified by a number assigned to each of two-dimensional optical detectors each of which is provided for a respective one of the holographic recording layers in order to detect the data pages which are angle-multiplex-recorded.  
   
   
       15 . The access method for a multi-layer holographic recording medium according to  claim 4 , wherein the layer number assigned to each of the holographic recording layers is identified by a number assigned to each of two-dimensional optical detectors each of which is provided for a respective one of the holographic recording layers in order to detect the data pages which are angle-multiplex-recorded.  
   
   
       16 . The access method for a multi-layer holographic recording medium according to  claim 2 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       17 . The access method for a multi-layer holographic recording medium according to  claim 3 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       18 . The access method for a multi-layer holographic recording medium according to  claim 4 , comprising: a process of simultaneously reading a plurality of the data pages which are angle-multiplex-recorded in the same recording area; and a process of shifting to the recording area to be read out.  
   
   
       19 . The access method for a multi-layer holographic recording medium according to  claim 2 , comprising: a process of successively reading a first data page to a last data page in the holographic recording layer; and a process of changing to the holographic recording layer to be read out.  
   
   
       20 . The access method for a multi-layer holographic recording medium according to  claim 3 , comprising: a process of successively reading a first data page to a last data page in the holographic recording layer; and a process of changing to the holographic recording layer to be read out.